As a conventional example of the exhaust gas analyzer of the aforementioned type, Patent Document 1 discloses a vehicle-mounted HC measuring apparatus. This vehicle-mounted HC measuring apparatus enables the mounting in the vehicle of: an NDIR (non-dispersive infrared) gas analyzer for continuously measuring HC (hydrocarbon) concentrations in the exhaust gas flowing in the exhaust tube connected to the engine; an exhaust gas flowmeter for continuously measuring the flow rate of exhaust gas flowing in the exhaust tube; and an operational processing circuit for continuously calculating the amount of THC (total hydrocarbon) in the exhaust gas by calculating the outputs of the NDIR gas analyzer and the exhaust gas flowmeter.
There are a variety of other exhaust gas measuring apparatuses and analyzers that employ the NDIR (non-dispersive infrared) method, the FID (flame ionization detector) method, or the CLD (chemical luminescence detector) method. These measuring methods in all their measurement principles require the use of reference gas.    Patent Document 1: JP Patent Publication (Kokai) No. 2004-117259A
The exhaust gas analyzer disclosed in Patent Document 1 measures the concentration of the THC component, for example, in the exhaust gas by sampling the exhaust gas in the exhaust path as it is emitted by the internal combustion engine of the vehicle running on the actual road, using infrared absorption or some other analysis technique.
However, in such exhaust gas analyzer, the flow of the exhaust gas in the exhaust path is stirred as the exhaust gas is sampled, thereby preventing a real-time analysis of the condition of exhaust gas as it flows in the exhaust path. As a result, it is impossible to measure the concentration of each component in the exhaust gas as it flows in the exhaust path after being emitted by the internal combustion engine.
It is therefore an object of the invention to provide an exhaust gas analyzer which enables the concentrations of components of the exhaust gas emitted by the internal combustion engine of an automobile or the like to be measured accurately as it flows in the exhaust path.